Continuous casting machine having billet shape maintaining rollers



July 23, 1968 F. w. RYS 3,393,727

CONTINUOUS CASTING MACHINE HAVING BILLET SHAPE MAINTAINING ROLLERS Filed Oct. 22, 1965 FIG. 6

INVENTOR.

FEEDR/CK m RYS United States Patent Office 3,393,727 CONTINUOUS CASTING MACHINE HAVING BILLET SHAPE MAINTAINING ROLLERS Frederick W. Rys, Pittsburgh, Pa., assignor to Koppel-s Company, Inc., a corporation of Delaware Filed Oct. 22, 1965, Ser. No. 501,851 1 Claim. (Cl. 164-282) ABSTRACT OF THE DISCLOSURE Continuous cast strands emerging from a casting mold are supported at their corners and along their flat surfaces, or, in the case of cylindrical or ovalar shaped strands, along arcs of the periphery of the strand in order to maintain the desired cross sectional shape of the strand until its skin develops suflicient thickness and the strand is stabilized.

Continuous cast strands having the preformed shape of a structural member are formed in the mold and supported in the same manner.

This invention relates generally to metal casting and more particularly to apparatus for use in the continuous casting of strands of metal, especially steel.

The conventional apparatus for casting a continuous strand of steel includes a casting mold which is vertically reciprocable, and into which molten metal is poured from a ladle and tundish arrangement; a cooling chamber directly below the mold, through which a continuous casting passes and wherein the casting is sprayed with cooling water; an apron structure within the cooling chamber on which the casting is supported; and a withdrawal mechanism such as a set of powered pinch rolls which engage and withdraw the casting in a continuous manner from the cooling chamber and mold.

Heretofore, the continuously cast billet was cooled immediately as it emerged from the mold, but it was not shaped, and in many instances the billet froze, having a rhombic cross section shape instead of the desired rectangular shape.

The present invention provides a novel support for the continuously cast billet which supports both the corners and the flat sides of the billet, and maintains the billet in the desired form until it freezes and becomes sufliciently solid throughout its cross section to stabilize its shape adequately.

For a further understanding of the present invention and for advantages and features thereof, reference may be made to the following description taken in conjunction with the accompanying drawing forming a part of the application which shows for the purpose of exemplification several embodiments of the invention.

In the drawing:

FIG. 1 is a schematic elevational view of a vertical casting mold incorporating one embodiment of the invention;

FIG. 2 is a view along line IIII of FIG. 1;

FIG. 3 is a schematic plan view, similar to the view of FIG. 2, of an embodiment of the invention adapted to guide and support an octagonal shaped billet;

FIG. 4 is a schematic plan view, similar to the view of FIG. 2, of an embodiment of the invention adapted to guide and support a cylindrical shaped billet;

FIG. 5 is a schematic plan view, similar to the view of FIG. 2, of an embodiment of the invention adapted to guide and support a billet in the shape of a preformed structural beam blank; and

FIG. 6 is a sectional view along line VIVI of FIG. 1.

FIG. 1 illustrates a conventional vertically reciprocable continuous casting mold 11 into which a stream of molten 3,393,727 Patented July 23, 1968 metal 13 may be poured from a conventional ladletundish arrangement (not shown), and from which a strand 15 of cast metal is being continuously withdrawn. The casting mold 11 is provided with the usual inlet 17 and outlet 19 conduits by means of which cooling fluid is introduced into the mold to cool the walls thereof.

In the continuous metal casting process, it is recognized that there is a first zone, designated as A in FIG. 1, of close intimate contact of the molten metal '13 with the walls of the mold. In this first zone, heat is rapidly transferred from the molten metal 13 to the cooling fluid within the mold wall cavity, and below the initial zone of contact A, the molten metal 13 solidifies and forms a thin skin 21 (FIG. 6). Below the region A, the outer surface of the casting cools and contracts and shrinks away from the intimate contact with the cooler mold walls that it had initially. And so, since the casting 15 is no longer in intimate contact with the mold walls below the zone A, the rate of heat transfer from the molten metal is accordingly reduced. The casting 15 radiates heat to the walls of the mold and the skin 21 continues to thicken progressively as the casting moves downward.

FIG. 6 is a cross section through a typical casting, taken at the level VI-VI within the casting mold 11, and illustrates the typical shape of a continuous cast strand 15 which is commencing to solidify into a rhombic shape but which was intended to be rectangular. The central portion 23 of the rhombic shaped steel strand is molten, and remains molten throughout a considerable length of the casting below the mold 11; the skin 21 being relatively thin in the region of the level VIVI.

It is understood of course that the skin 21 increases progressively in thickness inwardly as the casting descends, due to the forced cooling of the outer surface of the casting by means of water sprays which will be mentioned hereinafter.

A vertical cast steel strand has a relatively long molten core extending below the bottom of the mold. This is in great contrast to the condition present within a vertical continuously cast strand of other metals such as copper, aluminum, magnesium, and the like. Metals such as copper, aluminum and magnesium have a very shallow molten crater that is entirely resident within the boundaries of the mold. Actually, a continuously cast strand of metal such as copper, aluminum and magnesium, is entirely solid when it leaves the mold and such strands generally conform closely to the shape of the mold walls; whereas, a continuously cast strand of steel tends to assume the rhombic shape shown in FIG. 6, and mentioned previously.

However, continuous castings which are produced in accordance with the present invention are supported by the novel apparatus shown in the several embodiments of the drawings, and do not deviate appreciably from their initial shape as formed in the mold.

The embodiments of FIGS. 1 and 2 comprise a group of horizontally coplanar corner rollers 25 and a plurality of side rollers 27 which are journalled in suitable supporting brackets 29 that are secured to the bottom of the mold 11 in a conventional manner. Each corner roller 25 has a V-groove 31 in its peripheral surface and the included angle between the sides of the V-groove 31, in the embodiments of FIGS. 1 and 2, is Thus, these corner rollers 25, in association with the slab side rollers 27, tend to conform a strand which tend to have a rhombic shape 15, to a desired rectangular shape shown in FIG. 2. In the embodiments illustrated elsewhere in the drawings, the included angle of the groove in the rollers may be 45 as in FIG. 3, or the groove may be a circular are as in FIGS. 4 and 5.

In a particular installation, there may be a plurality of groups of corner 25 and side 27 rollers as suggested in FIG. 1, arranged in vertical spaced apart relation. Preferably, the groups are spaced together as closely as is practicable, leaving just enough vertical space for the usual arrangement of cooling water spray nozzles 33. It is preferable to attach the first or uppermost set of corner and side rollers 25, 27 to the bottom of the mold 11, because they are thus able to reform the strand, which tends to have the rhombic cross sectional configuration as illustrated in FIG. 6, as a rectangle as soon as it emerges from the mold and while the skin 21 is not too thick to resist reforming. The lower sets of corner and side rollers 25, 27 are preferably fixed to any suitable frame structure 35, shown schematically in FIG. 1. In some applications it may be desirable and preferable to so position the corner and side rollers 25, 27 that they engage the strand at an upper level within the mold walls, such as within the region below 'zone A and the bottom of the mold.

While the embodiment of FIG. 1 suggests that the cast strand descends substantially vertically, it is to be understood that, in accordance with the teachings in a copending application Ser. No. 381,620, filed July 10, 1964, the path of the continuous cast strand 15 may be expected to change from the vertical attitude to the horizontal attitude Without using the conventional bending roller mechanism (not shown), and that the corner and side rollers 25, 27 merely reform the cast strand to a desired shape, usually rectangular, and do not exert a bending force on the casting as might be expected.

It will be recognized then, that the corner 25 and side 27 rollers accomplish several purposes such as: reforming the newly formed pliable cast strand to a desired cross sectional shape; maintaining the cast strand within a prescribed path of travel while the skin 21 continues to thicken as a result of the spray-nozzle cooling arrangement 33; and supporting the cast strand when the skin is thinnest and weakest.

FIGS. 3, 4 and 5 illustrate different embodiments of the invention as adapted to: a continuous casting 37 having an octagonal cross section (FIG. 3); a continuous casting 39 having a circular cross section (FIG. 4); and a continuous casting 41 having the preformed cross sectional shape of a structural H-beam (FIG. 5).

The continuous octagonal strand 37 is reformed by a plurality of vertical arranged groups of coplanar corner rollers 43 in each of which there is a groove 45 having an included angle of 45 between the sides of the groove. Each corner roller 43 is journally mounted in suitable support brackets 47, which may be similar to the brackets 29 indicated in FIG. 1. While there are no side rollers in the embodiment shown in FIG. 3, it may be desirable to provide such side rollers in some instances, particularly whenever the lateral unsupported side surface of the strand, between adjacent corner rollers, is excessive. Such side rollers would in accordance with the invention be coplanar with a group of corner rollers 43 at a respective level.

Likewise, the strand 39, having a circular cross section,

utilizes a plurality of rollers 49 each of which is journally mounted in support brackets 51 and has a biconcaval cross sectional outline, about as shown in FIG. 4.

The preformed structural member 41 of FIG. 5 is illustrated, for the purposes of this application, as an H-beam blank and utilizes a plurality of corner rollers 53 that are adapted to the rounded end forms of the flanges of the preform H-beam, and a pair of opposed side rollers 53 that engage the web portion of the preformed H-beam blank.

It will be recognized by those skilled in the art that other preformed continuous cast strands may have the shape of I-beams, channels, Z-bars, angles, and the like; each of which utilizes a plurality of groups of appropriately shaped corner rollers and side rollers, about as shown in FIG. 5.

That continuous castings having the shape of partially formed structural beams can be made and supported in accordance with the present invention is of great signifi- 4 cance in the art of steel casting. For example, a casting formed and supported in accordance with the invention could eliminate several of the rolling steps now required to form the structural beam. Such a saving can be of great economic significance in the steelmaking art.

The type ofroller supporting apron used heretofore is recognized as not being readily adaptable to support a preformed structural beam blank, but, however, the present invention overcomes this inadequacy. The usual rhombic shaped billets, as well as such preformed beam blanks, can be readily reformed as rectangular billets and these can be supported in an effective and satisfactory manner.

While the foregoing has described the invention in relation to a vertical casting mold 11, having an internal casting cavtiy that has substantially vertical planar walls, the invention is not so limited. Actually, the casting mold 11 may have an internal cavity formed by substantially parrallel arcuate walls, or walls which taper slightly. Associated with such arcuate mold there may be both cornersupporting and lateral-surface supporting rollers which may be similar to the types of rollers described hereinbefore.

Likewise, a horizontal casting mold may be used with which both corner and lateral supporting rollers or the type described previously may be affixed to the mold in the manner indicated hereinbefore.

While in the embodiment shown in FIGS. 1 and 2, only two pairs of opposed side rollers at different levels engage the lateral surfaces of the rectangular shaped casting, it should be understood that additional pairs of lateral surface engaging rollers may be utilized whenever the width of the casting is considerably greater than its thickness.

The present invention may also be utilized to guide continuous castings in the form of hollow tubes, as well as solid castings having other geometrical cross-sectional shapes, such as ovals and squares.

From the foregoing it should be apparent that the apparatus of the invention provides a simple and effective solution to the problem of casting a continuous strand that will have a rectangular or other preferred shape. The usual continuous casting apparatus heretofore available is not entirely effective and is inadequate to reform a continuously cast steel strand that has deviated from a preferred shape, since there is no support at the corners of the strand, and the corners are the region wherein most of the shape deformity occurs. The present invention is adaptable also to support continuous cast strands having many various cross sectional shapes. One set of corner rollers can be readily replaced by another set of corner rollers when the mold shape is changed and the shape of the cast strand is changed.

Although the invention has been described herein with a certain degree of particularity, it is understood that the present disclosure has been made only as an example and that various modifications and changes may be made within the scope of the invention as defined by the appended claim.

What is claimed is:

1. In continuous metal casting apparatus, the improvement comprising:

(a) a vertically reciprocable casting mold wherein molten metal partially solidifies and forms a continuous cast strand having a cross section that simulates a structural shape havin ga web portion and flange portion;

(b) a pair of spaced apart coplanar first rollers having parallel first axes engaging opposite sides of said web portion; and

(c) second rollers engaging the extremities of the flange portion and having secondaxes parallel to the first axes;

(i) both said first and second rollers maintaining the original shape of said cast strand as it emerges from said mold.

(References on following page) 5 6 References Cited 674,136 4/1939 Germany. 746,027 12/1944 Germany. UNITED STATES PATENTS 950,882 2/1964 Great Britain. 2,707,813 5/1955 D1cks0n 164282 3,015,862 1/1962 Rusterneyer e161. 164-283 5 OTHER REFERENCES 431,179 7/ 1890 Bickley 722 Iron and Steel, v01. 37, N0. 14, December 1964, TS

FOREIGN PATENTS 300-16219611- 132 9 3/196 r nc J. SPENCER OVERHOLSER, Primary Examiner.

Zflggi 10 R. s. ANNEAR, Assistant Examiner. 

